title: Uncertainty in nuchal translucency reference ranges at 11-14 weeks of gestation--comparison to Swedish centiles.
abstract: OBJECTIVE
  To generate a regression equation for the nuchal translucency (NT) median for the Swedish population and compare this with other median values.
  
  
  METHODS
  Eight Swedish hospitals.
  
  
  METHODS
  The data set included 20 887 unaffected fetuses.
  
  
  METHODS
  Calculation and generation of an NT centile chart for the Swedish population.
  
  
  RESULTS
  The NT centiles for crown-rump length (CRL) from 45 to 84 mm were calculated and compared with the medians from Glasgow, from the Fetal Medicine Foundation (FMF, London, UK; FMF-original) and those published recently (FMF-new). The NT medians cease to increase at CRLs between 70 and 75 mm. The Swedish, FMF-new and Glasgow medians followed the same pattern, but the Glasgow NT median curve was systematically lower by around 20%. Swedish, FMF-new and Glasgow medians differed in shape from the FMF-original medians, which continuously increase throughout the whole range of CRLs.
  
  
  CONCLUSIONS
  Our results demonstrate that there are substantial differences in the NT medians and centiles between countries.
authors.affiliation: Center of Fetal Medicine, Karolinska University Hospital, Huddinge, Stockholm, Sweden. marius.kublickas@ki.se
authors.forename: Marius
authors.initials: M
authors.lastname: Kublickas
authors.forename: Sissel
authors.initials: S
authors.lastname: Saltvedt
authors.forename: Harald
authors.initials: H
authors.lastname: Almström
authors.forename: Charlotta
authors.initials: C
authors.lastname: Grunewald
authors.forename: Jennifer
authors.initials: J
authors.lastname: Crossley
mesh_terms: D000328:Adult; D018568:Crown-Rump Length; D005260:Female; D005865:Gestational Age; D006801:Humans; D008432:Mathematical Computing; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011248:Pregnancy Complications / Q000000981:diagnostic imaging*; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D012044:Regression Analysis; D012494:Sampling Studies; D013548:Sweden / Q000453:epidemiology; D035501:Uncertainty; D006113:United Kingdom / Q000453:epidemiology